Well, I think we can put this one to rest. I have verified that the square around the gear designation letter disappears and the OD OFF light starts blinking after some time of driving with the gear shifter somewhere between D and 3. It's somewhat disconcerting to me that it is even possible to shift this way and I will mention this during the next oil change but for now I can live with this. For the curious, to be sure that the shifter is in proper position, one has to (1) pull the shifter inward, (2) move the shifter to D and then (3) push the shifter outward. The step #3 is something I wouldn't normally do but it seems necessary with the shifter in MPV.
I do have one remaining concern however. It has to do with the hesitation we have experienced when trying to accelerate from a dead stop. For now, my thinking is that it may have been caused by the confused module when the shifter was between D and 3. Time will tell...
Thanks for the chuckle! I'm still ROFLMAO! (Don't know if the pun was intended or not?) FWIW, my MPV's exhaust is no stinkier (sp?) than my Accord, both using the local cut-throat discount gas station.
bad gas is really a problem here in the US...Most consumers dont realize that many sates wont allow just normal gas to be sold....last time I checked we sold over 60 different variations of gasoline in the US.
Here in CT they require gas with some chemical called MTBE which was rammed down our throats in the name of cleaner air. The fact is this checmical is now leaking out of gas tanks and it will be the next big lawyer jackpot...also it wont allow a car to run at its peak performance.
The 2001 Honda Accord Owners Manual asks owners to be careful while fueling up in Canada because of the presence of the MTBE additive (used to boost octane ratings). As per the manual, this can damage the emissions control system. However, I had no inkling that we have this problem in Connecticut too!
Nice article, thanks. I wonder what are the figures for US gas. From the quoted article it appears that Petro-Canada produces not so good gas as far as sulfur content is concerned, but I used this brand quite a lot (a gas bar is just across the road from my home) and I never smelt rotten eggs in 2 years of ownership. I believe if there was any flaw in emission control system on MPV that caused this, I would have had it as well, because mine is a rather early production (built Nov 1999). So, I wonder why a lot of people complain about sulphur smell? If that's not fuel, then what?
"Motorists who care about their family's health should send a message to Imperial Oil by avoiding ESSO gasoline during the summer smog season," said Beatrice Olivastri, Chief Executive Officer of FOE.http://www.foecanada.org/media/000419.htm
Guys, the octane rating only applies to anti-knock compounds not detergents or other additives. Regular gas is not dirtier and does not contain less detergents only less anti-knock compounds. I would just try different brands if the smell does not go away. Also the smell may go away as the weather gets warmer. The gas companies change the formulas for warm and cold weather due to emmisions requirements.
joe2617, premium gas contains additional detergents. Until 1995 in US adding detergents was voluntary and lower grades of gas often didn't have any detergents. Since 1995 federal law mandates adding detergents to all gasoline sold in US. That does not mean all grades of gas have the same additives. I am quoting from Mobil website:
Gasoline FAQs
Why should I use Mobil Super+ instead of Mobil Regular or Mobil Special? Compared to Mobil Regular and Mobil Special, Mobil Super+ is different in two ways. (1) It has a higher octane rating and, (2) it contains additional detergent additives.
Arrrrgh! I just got outbid on ebay for an oem 6disk MPV stereo. If the winner is on this board, congrats! I'll be sending Bob57's soccer team to you soon for a visit (just kidding, of course!) Take heart Java, he paid more than you did!
Thanks to all. I have an appointment next week to get this bugger fixed - the parts have been ordered. It was so funny when it actually stuck for the service manager when I brought my MPV in to request the fix. That's gotta be a first for me!
Soccer team on rest right now - everyone safe... BTW, my wife's team (and daughter) won State chamionship last week. While on the subject (?) does anyone know why Mazda killed the red in 2002? A couple of people asked me about that when they saw mine and went shopping. "That's the reddest red I ever saw..".
Seeing the MPV problem postings near the peak interest is enuf to make an expectant MPV owner get heart palpatations . It is good to know there isn't much to talk about except red color and stinky exhaust smoke.
The ody board is replete with tranny problems, power door failures, check engine issues.... nice to be ignorant of such problems with the MPV.
BTW beachnut, my MPV will be coming with a 6 cd changer that I doubt we will use... just have to figure out how to deal with our buddy Steve lol.
I never thought we would use the CD changer either,it just happened to be on the van we bought off the lot, but we got a new computer and a new van about 6 weeks apart and discovered the exciting world of downloading music and CD burning. Needless to say, that CD changer is getting a workout! Unfortunately we have almost 2,000 miles and still have the sulfur smell. I have tried almost every brand of gas available in this area. Some are worse than others, but it never completely disappears. So far, no other problems at all. I love my 2nd MPV even more than the 1st one.
I was working a soccer tournament this weekend and saw a (I thought) new sand colored '02 MPV pull in beside my '01. As I got closer I saw that it was an '01 but looked like it was showroom new. Suspecting it was just purchased I asked the driver how she liked her new MPV. "New"? she said, "It's got 36,000 miles and not even a year old yet. I love this thing - zero problems".
About colors; Toyota had a special order color that the salesman said was "Ice blue". Now that would be nice too - Maybe call it "Java/Winter Blues" or something. That sounds like a song title... )
Don't know what's up with Java ... he hasn't been the same since returning from Hawaii. Suppose I can understand, leaving paradise would be hard for me too ....
You should feel sorry for me, lol. It's pure torture. The only truly enjoyable item is sending cold weather to that SMALL Southern state that rythms with nexus. Nothing to do here but sit on my deck and sip cold ones, fish, plan to fish and fish some more. :-P That reminds me, I need to go fishing.
I tell ya, MochaVan has been so handy lately! I put in laminate floors (in the HOUSE not the van... I had to clarify for you characters) this past week, and I couldn't have done the project w/out the great cargo space of the MPV. Man, that thing sucks up stuff. OSB, no problem (mostly). 8ft trim and molding? Bring it. 600lbs of planks? Fahgietabaahhtit! Then, the youngest java-runt had a birthday and I just had to get her this battery powered VW, and the requisite bazillion helium balloons. Of course, it couldn't fit in the Volvo, but no problemo in MochaVan.
Beach, quit pounding the dashboard of your van, others might stare. ;-)
Just bought a new 2002 MPV ES. Van is great all around. Only one annoying thing though...
There is a plastic "valence" under the steering wheel thats about 12" X 12" that is removeable. It has "come loose" about 10 times in one week. I keep snapping it back in place. Come back later and it is loose again. I don't want to super glue this thing in place but its such a minor problem I hate to drag it to the dealer.
Excalibur, I am not sure what piece are you talking about. I don't see anything 12"x12" under the steering wheel. Nevertheless, if it is coming loose you should tell a dealer while you changing oil. It should be no big deal to fix it.
I see the item Excalibur is talking about - it's the cover directly under the steering column held on by clips - I think it's clips by feel only - didn't want to crawl under and spill my martini... Yes - take it to the dealer.
JAVA: ah...you makin' fun of us Texas boys again? Gonna send you a bayou catfish so you know what a real fish looks like...maybe one of them gators in the backyard - as soon as I find my hound dog....
Got an excuse to get my loose valence fixed now. Got call from hell from 9 month pregnant wife at noon today. Pulled out of grocery store and O/D light is flashing and transmission is jerking her around. She pulled over and had van towed to dealer.
I remember reading about this somewhere on some board. Has anyone had any similar experiences and what was wrong, etc.
Van is 2002 MPV ES still on first tank of gas - about 250 miles
Hopefully it's just a rare glitch Exe. Smart woman, not driving it when it's jerking about like that. And, really not what she's wanting to deal with when she's so far along, eh?
Someone did post here or 'the other' message board w/in the past couple of weeks, but I thought they solved their problem by making sure they were being precise w/their gear selector position. I could be wrong... but somewhere to start nonetheless. Hopefully, the computer keeps the codes from the transmission's messages, that would be additionally helpful.
BWT, if your d.w's still steaming when your lawn's mowed, mine could use a trim. ;-)
From time to time I have read comments that say something to the effect, "I drove an MPV with 16" wheels and it rides much better than the 15" wheels."
QUESTIONS: (1) I am also told that the total diameter of the mounted tire with 15", 16" and 17" wheels is the same--the difference to accomplish this being in the height of the tire wall from the wheel rim out to the tread. If this is true. . .
(2) Why would it ride better on what is essentially less air?, and. . .
(3) Would the 16" or 17" wheels have any effect on "handling"? The steering (handling) of my 2002 LX is VERY sensitive, and unless you pay close attention it sometimes (especially in gusty winds) seems to "wander" a bit. Tho I love it dearly, for some reason it does not seem to track with the flawless stability of my 94 Olds Ciera wagon. Would 16" or 17" wheels have any appreciable effect on this, or is the car's handling just the sensitive nature of the Mazda steering mechanism? Solid factual advice on this, anyone????
It's probably more a function of the tires, your tire pressure, and your alignment.
Some tires seem to find every crack and crevice in the road and try to follow it.
You do mention wind, your van has a lot more surface area than the Olds wagon, so it is more sensitive to the wind.
First, check your tire pressure with a really good gauge, not the $2 ones at Walmart. You can get a fairly decent one for around $10, if you don't already have one. Use it every Saturday when you check out your vehicle for lights working and such. 8^) Of course, check them cold. That's why Saturday morning is a good time. Unless you work the night shift, the adjust accordingly.
Check your air pressure and make sure they are the same as specified on the door/manual for the vehicle.
If that's all good, then drive the van. If you notice it darting a particular way, check the road surface. Does the road have a crown in it that slopes one way. If there are other lanes, do they have a crown that goes the other direction? If so, drive over there (when safe) and see if the behavior is the same or changes.
What direction is the wind? Is it a cross wind, partially a crosswind, you should get the idea.
The drive back on the same road in the other direction. If it is a wind issue, any pull should be in the other direction.
I've not noticed our MPV to wander, but it is very sensitive to the wind.
Oh, trucks and overpasses may create little "Low Pressure Zones" where you seem to get sucked in before you are blown back.
If none of this explains it, then see your dealer and tell him what you've already tried.
Of course, better ride is subjective. My Grandmother who loves her Mercury Grand Marquis would just love the 15" tires with the pillow like ride (relative to the 17" tire.)
A 17" wheel means a shorter sidewall. This means better steering response, most likely more road feel and such. The downside is the ride will be more harsh. (Some people don't like road feel. I don't understand those people 8^) )
And of course, you've hit upon one of the most important characteristics of your tires, the air they hold. It is the air pressure in your tires that support the weight of your van. In an ideal world with 50/50 weight and a loaded van weighing 4000#, each corner supports rougly 1000#. If you have 40 PSI in your tires (for nice round numbers) you then have about a 25 square inch contact patch at each tire. Or about 100 square inches total.
But it is the pressure, not the volume of air that supports the vehicle.
What typically happens is the shape of that contact patch changes. People with the 17" wheel may have a wider tire, so the patch is wider, but is shorter from front to back. This also improves cornering and braking, but drops fuel economy and may hydroplane easier. It also reduces traction on snow.
Tboner, I am not picking on you but you made a statement that .... 17" wheel .... improves cornering and braking, but drops fuel economy and may hydroplane easier Would you please point us to the references where it would say that 17" will have inferior hydroplaning resistance in comparison to 15" or 16" tire?
I do believe I've been quoted out of context here, the stuff you left out really changes the meaning of what I said here. (Leaving out the direct object really changes what I said, don't you think? I was talking about the contact patch. Perhaps I wasn't clear.)
Given two tires that are identical tread pattern, the wider tire will have a greater tendancy to ride up on the water surface.
The narrower tire, can cut through the water easier.
A wider tire picks up and puts down more rubber in the same distance because the contact patch is wider.
A narrow tire will have longer patch, so less of the tire is being picked up and put down in that same space of time.
This causes greater friction (because basically, traction is a measure of a tires friction)
And just as a point. I didn't say a 15" would be superior. I said a wider tire will experience these behaviors. It is not a function of the rim width, but that of a wider tire.
Just for clarification, here is what I said People with the 17" wheel may have a wider tire, so the patch is wider, but is shorter from front to back. This also improves cornering and braking, but drops fuel economy and may hydroplane easier. It also reduces traction on snow.
However, the final thing to consider is the rotating mass. If the 17" wheel/tire combination is heavier than a smaller diameter, you have more losses in the drive train. Acceleration can suffer if you install a heavier wheel tire combo, not to mention fuel economy. Finally, a 17" rim may put more mass further away from the center of the wheel. The mass is harder to move and to stop, if it is shifted out from the center of the wheel. A 15" wheel/tire combination, of the same weight as a 17" wheel/tire combo, but have a more favorable distribution, due to more of the tire's mass closer to the center of the rim. I believe the forces involved here increase as a square property to the distance from the rotational axis, so the further out from the hub the mass is, the greater impact it has on rotating the entire mass.
But I never said the 17" rim, by it self, causes these thing. Rather, I said the typical application of wider tires, combined with the taller wheel does.
I have/had the same problem. It turned out that the gear lever can be placed somewhere between D and 3, which causes the O/D OFF light to start flashing after a while. Also, the square around the gear designation letter disappears. After a while of driving like this, the transmission starts acting up. Remember that this transmission is not only, unfortunately, automatic but also electronic and adaptive, which probably means there is a computer that thinks for you and screws up most of the time.
I do love this country but I just can't understand this automatic everything thing. ATs cost more money, are more complex and ARE NO FUN!!!!
Well it is not really clear to me. I am only talking about hydroplaning effect. Simple physics state that the size of the surface has nothing to do with the force of friction. Friction depends on the coefficient of friction, which is different for each kind of material, and from the weight, which is the force one object exerts on another. I don't want to get here in coefficient of static friction or coefficient of dynamic friction. The point I am trying to make is that the width of the tire has nothing to do with hydroplaning.
I have tried to put the lever between D and 3 and I am not able to do that. It will not stay in between position. It will either go to D or 3. As a matter of the fact I am unable to do that in any "between" position. Possibly this is the problem that some Mazdas have gear lever defective.
but it does have to do with how much tread you are putting down during a given unit of time.
However, probably the most important aspect is the tread pattern, and which way a tire evacuates water.
If a tread patter forces a tire to evacuate water from side to side, instead of front to back, the wider tire will have a greater tendancy to hydroplane, simply because it cannot evacuate the water fast enough. More distance to travel.
However, I do agree that if a tire has a more clear path in the tread, from front to back, it may evacuate water quicker from front to back. Since this is a shorter path in the wider tire, it may not hydroplane as easily.
However, I still believe, in most cases, a wider tire, suddenly encountering a puddle at high speeds, has a greater propensity for hydroplaning, simply because the rate of change of tread surface moving across the road is greater. A narrow tire will leave any given portion of the tread surface on the road longer than the narrow tire because the tread pattern is long and narrow. So you have a smaller area trying to force out new water from the voids in the tire. The wider tire is laying down more rubber per unit time. So it has to force out the water it encounters at a quicker rate.
If the two tires in question have the same tread pattern, I believe in most cases, the narrower tire will do a better job of preventing hydroplaning.
The friction discussion above was meant to explain why you might experience a drop in fuel economy using a wider tire. Not to mention that drag increases 4x when speed doubles. There would be an ever so slight increase in drag with a wider tire. But I even admit that is a bit of a stretch.
However, you don't see wide front tires on top fuel dragsters.
TB, here's a quote from the last link you posted: Tread void refers to the grooves in the tread pattern where no rubber is in contact with the road, allowing water to be channeled and ejected from the footprint. Adding void permits higher speeds before hydroplaning occurs but removes rubber from the road, which reduces wet and dry traction.
So if you assume a narrower tire is really a wide tire with lots of void at the edges, this supports that wide tires hydroplane at lower speeds.
Also, notice that the aquatread, etc., tires tend to have voids that completely circle the tire. These are the "channels" that goodyear and others brag about. Essentially these channels make the tire narrower.
And a little anecdotal evidence. When I had my Festiva, it *rarely* hydroplaned. I traded it for my del Sol, which is about the same weight (same weight and same tire pressure equates to same size contact patch), and the del Sol hydroplaned much more often. The tire width on the Festiva was 145 or 155 (depending on which tires I had on it), and the width on the del Sol is 185. Now, there are tire diameter and profile differences, so this isn't a scientific comparison, but that's my experience.
And I think that it's not the contact patch that is the issue with hydroplaning. I think the issue is about how much of the tire is in contact with the *water*. A wider, larger-diameter tire (not wheel) will have more rubber contacting the puddle than a narrower, smaller-diameter tire. What's the tire diameter have to do with it? Well, just ahead of the contact patch, the rubber approaches the road at an angle. On smaller diameter tires, that angle is larger (with respect to the road), and therefore exposes less rubber to the water. The larger diameter tire's "approach angle" is a smaller angle and exposes more rubber to the water.
Comments
I do have one remaining concern however. It has to do with the hesitation we have experienced when trying to accelerate from a dead stop. For now, my thinking is that it may have been caused by the confused module when the shifter was between D and 3. Time will tell...
kcz
Here in CT they require gas with some chemical called MTBE which was rammed down our throats in the name of cleaner air. The fact is this checmical is now leaking out of gas tanks and it will be the next big lawyer jackpot...also it wont allow a car to run at its peak performance.
http://www.cbc.ca/consumers/market/files/cars/lowsulphurgas/index.html
There must be more to the story than that.
http://www.rcdzone.net/sunoco.nsf/pItem/8195395FDCC1E51985256B5E005224FC
"Motorists who care about their family's health should send a message to Imperial Oil by avoiding ESSO gasoline during the summer smog season," said Beatrice Olivastri, Chief Executive Officer of FOE.http://www.foecanada.org/media/000419.htm
MB
Well, just because you are buying gas at the Petro-Canada gas bar doesn't mean they refined it. The stations and refineries all trade around...
http://www.cbc.ca/consumers/market/files/cars/lowsulphurgas/table.html
Gasoline FAQs
Why should I use Mobil Super+ instead of Mobil Regular or Mobil Special?
Compared to Mobil Regular and Mobil Special, Mobil Super+ is different in two ways. (1) It has a higher octane rating and, (2) it contains additional detergent additives.
MB
BTW, my wife's team (and daughter) won State chamionship last week.
While on the subject (?) does anyone know why Mazda killed the red in 2002? A couple of people asked me about that when they saw mine and went shopping. "That's the reddest red I ever saw..".
As an aside, I'm seeing aLOT more MPVs on the road these days.
/j
;>>
RJ
B&G Club soccer starts next week, so I get to use the tailgater seat, yay!!! (pseudo-reqcon)
/j
Steve
Host
SUVs, Vans and Aftermarket & Accessories Message Boards
/j hey, you're straying me off topic, lol.
The ody board is replete with tranny problems, power door failures, check engine issues.... nice to be ignorant of such problems with the MPV.
BTW beachnut, my MPV will be coming with a 6 cd changer that I doubt we will use... just have to figure out how to deal with our buddy Steve lol.
jw
Steve
Host
SUVs, Vans and Aftermarket & Accessories Message Boards
About colors; Toyota had a special order color that the salesman said was "Ice blue". Now that would be nice too - Maybe call it "Java/Winter Blues" or something. That sounds like a song title...
Don't know what's up with Java ... he hasn't been the same since returning from Hawaii. Suppose I can understand, leaving paradise would be hard for me too ....
Steve
Host
SUVs, Vans and Aftermarket & Accessories Message Boards
I'm starting to get an annoying dash rattle under the speedo. My hand still hurts - but it persuaded the rattle to be quiet, at least for now ;(
I tell ya, MochaVan has been so handy lately! I put in laminate floors (in the HOUSE not the van... I had to clarify for you characters) this past week, and I couldn't have done the project w/out the great cargo space of the MPV. Man, that thing sucks up stuff. OSB, no problem (mostly). 8ft trim and molding? Bring it. 600lbs of planks? Fahgietabaahhtit! Then, the youngest java-runt had a birthday and I just had to get her this battery powered VW, and the requisite bazillion helium balloons. Of course, it couldn't fit in the Volvo, but no problemo in MochaVan.
Beach, quit pounding the dashboard of your van, others might stare. ;-)
/j
Steve
Host
SUVs, Vans and Aftermarket & Accessories Message Boards
/j
There is a plastic "valence" under the steering wheel thats about 12" X 12" that is removeable. It has "come loose" about 10 times in one week. I keep snapping it back in place. Come back later and it is loose again. I don't want to super glue this thing in place but its such a minor problem I hate to drag it to the dealer.
Any similar experiences / solutions?
MB
Yes - take it to the dealer.
JAVA: ah...you makin' fun of us Texas boys again? Gonna send you a bayou catfish so you know what a real fish looks like...maybe one of them gators in the backyard - as soon as I find my hound dog....
Got an excuse to get my loose valence fixed now.
Got call from hell from 9 month pregnant wife at noon today. Pulled out of grocery store and O/D light is flashing and transmission is jerking her around. She pulled over and had van towed to dealer.
I remember reading about this somewhere on some board. Has anyone had any similar experiences and what was wrong, etc.
Van is 2002 MPV ES still on first tank of gas - about 250 miles
thanks,
Excalibur
Someone did post here or 'the other' message board w/in the past couple of weeks, but I thought they solved their problem by making sure they were being precise w/their gear selector position. I could be wrong... but somewhere to start nonetheless. Hopefully, the computer keeps the codes from the transmission's messages, that would be additionally helpful.
BWT, if your d.w's still steaming when your lawn's mowed, mine could use a trim. ;-)
/j
QUESTIONS: (1) I am also told that the total diameter of the mounted tire with 15", 16" and 17" wheels is the same--the difference to accomplish this being in the height of the tire wall from the wheel rim out to the tread. If this is true. . .
(2) Why would it ride better on what is essentially less air?, and. . .
(3) Would the 16" or 17" wheels have any effect on "handling"? The steering (handling) of my 2002 LX is VERY sensitive, and unless you pay close attention it sometimes (especially in gusty winds) seems to "wander" a bit. Tho I love it dearly, for some reason it does not seem to track with the flawless stability of my 94 Olds Ciera wagon. Would 16" or 17" wheels have any appreciable effect on this, or is the car's handling just the sensitive nature of the Mazda steering mechanism? Solid factual advice on this, anyone????
Some tires seem to find every crack and crevice in the road and try to follow it.
You do mention wind, your van has a lot more surface area than the Olds wagon, so it is more sensitive to the wind.
First, check your tire pressure with a really good gauge, not the $2 ones at Walmart. You can get a fairly decent one for around $10, if you don't already have one. Use it every Saturday when you check out your vehicle for lights working and such. 8^) Of course, check them cold. That's why Saturday morning is a good time. Unless you work the night shift, the adjust accordingly.
Check your air pressure and make sure they are the same as specified on the door/manual for the vehicle.
If that's all good, then drive the van. If you notice it darting a particular way, check the road surface. Does the road have a crown in it that slopes one way. If there are other lanes, do they have a crown that goes the other direction? If so, drive over there (when safe) and see if the behavior is the same or changes.
What direction is the wind? Is it a cross wind, partially a crosswind, you should get the idea.
The drive back on the same road in the other direction. If it is a wind issue, any pull should be in the other direction.
I've not noticed our MPV to wander, but it is very sensitive to the wind.
Oh, trucks and overpasses may create little "Low Pressure Zones" where you seem to get sucked in before you are blown back.
If none of this explains it, then see your dealer and tell him what you've already tried.
HTH
TB
A 17" wheel means a shorter sidewall. This means better steering response, most likely more road feel and such. The downside is the ride will be more harsh. (Some people don't like road feel. I don't understand those people 8^) )
And of course, you've hit upon one of the most important characteristics of your tires, the air they hold. It is the air pressure in your tires that support the weight of your van. In an ideal world with 50/50 weight and a loaded van weighing 4000#, each corner supports rougly 1000#. If you have 40 PSI in your tires (for nice round numbers) you then have about a 25 square inch contact patch at each tire. Or about 100 square inches total.
But it is the pressure, not the volume of air that supports the vehicle.
What typically happens is the shape of that contact patch changes. People with the 17" wheel may have a wider tire, so the patch is wider, but is shorter from front to back. This also improves cornering and braking, but drops fuel economy and may hydroplane easier. It also reduces traction on snow.
HTH
TB
braking, but drops fuel economy and may hydroplane easier Would you please point us to the references where it would say that 17" will have inferior hydroplaning resistance in comparison to 15" or 16" tire?
MB
Given two tires that are identical tread pattern, the wider tire will have a greater tendancy to ride up on the water surface.
The narrower tire, can cut through the water easier.
A wider tire picks up and puts down more rubber in the same distance because the contact patch is wider.
A narrow tire will have longer patch, so less of the tire is being picked up and put down in that same space of time.
This causes greater friction (because basically, traction is a measure of a tires friction)
And just as a point. I didn't say a 15" would be superior. I said a wider tire will experience these behaviors. It is not a function of the rim width, but that of a wider tire.
Just for clarification, here is what I said People with the 17" wheel may have a wider tire, so the patch is wider, but is shorter from front to back. This also improves cornering and braking, but drops fuel economy and may hydroplane easier. It also reduces traction on snow.
However, the final thing to consider is the rotating mass. If the 17" wheel/tire combination is heavier than a smaller diameter, you have more losses in the drive train. Acceleration can suffer if you install a heavier wheel tire combo, not to mention fuel economy. Finally, a 17" rim may put more mass further away from the center of the wheel. The mass is harder to move and to stop, if it is shifted out from the center of the wheel. A 15" wheel/tire combination, of the same weight as a 17" wheel/tire combo, but have a more favorable distribution, due to more of the tire's mass closer to the center of the rim. I believe the forces involved here increase as a square property to the distance from the rotational axis, so the further out from the hub the mass is, the greater impact it has on rotating the entire mass.
But I never said the 17" rim, by it self, causes these thing. Rather, I said the typical application of wider tires, combined with the taller wheel does.
Clear?
TB
I do love this country but I just can't understand this automatic everything thing. ATs cost more money, are more complex and ARE NO FUN!!!!
-- kcz
MB
MB
However, probably the most important aspect is the tread pattern, and which way a tire evacuates water.
If a tread patter forces a tire to evacuate water from side to side, instead of front to back, the wider tire will have a greater tendancy to hydroplane, simply because it cannot evacuate the water fast enough. More distance to travel.
However, I do agree that if a tire has a more clear path in the tread, from front to back, it may evacuate water quicker from front to back. Since this is a shorter path in the wider tire, it may not hydroplane as easily.
However, I still believe, in most cases, a wider tire, suddenly encountering a puddle at high speeds, has a greater propensity for hydroplaning, simply because the rate of change of tread surface moving across the road is greater. A narrow tire will leave any given portion of the tread surface on the road longer than the narrow tire because the tread pattern is long and narrow. So you have a smaller area trying to force out new water from the voids in the tire. The wider tire is laying down more rubber per unit time. So it has to force out the water it encounters at a quicker rate.
If the two tires in question have the same tread pattern, I believe in most cases, the narrower tire will do a better job of preventing hydroplaning.
The friction discussion above was meant to explain why you might experience a drop in fuel economy using a wider tire. Not to mention that drag increases 4x when speed doubles. There would be an ever so slight increase in drag with a wider tire. But I even admit that is a bit of a stretch.
However, you don't see wide front tires on top fuel dragsters.
TB
This seems to indicate, unless I totally miss my math, that a wider patch requires more speed to support hydroplaning.
Back to the drawing board
TB
Good explanation Tb!
/j
TB
I still want to believe give two different widths of the same tire on the same vehicle, the narrower of the two will be less likely to hydroplane.
I just can't find the physics to prove it ;(
Am I all wet, or what am I missing?
TB
here's a quote from the last link you posted:
Tread void refers to the grooves in the tread pattern where no rubber is in contact with the road, allowing water to be channeled and ejected from the footprint. Adding void permits higher speeds before hydroplaning occurs but removes rubber from the road, which reduces wet and dry traction.
So if you assume a narrower tire is really a wide tire with lots of void at the edges, this supports that wide tires hydroplane at lower speeds.
Also, notice that the aquatread, etc., tires tend to have voids that completely circle the tire. These are the "channels" that goodyear and others brag about. Essentially these channels make the tire narrower.
And a little anecdotal evidence. When I had my Festiva, it *rarely* hydroplaned. I traded it for my del Sol, which is about the same weight (same weight and same tire pressure equates to same size contact patch), and the del Sol hydroplaned much more often. The tire width on the Festiva was 145 or 155 (depending on which tires I had on it), and the width on the del Sol is 185. Now, there are tire diameter and profile differences, so this isn't a scientific comparison, but that's my experience.
And I think that it's not the contact patch that is the issue with hydroplaning. I think the issue is about how much of the tire is in contact with the *water*. A wider, larger-diameter tire (not wheel) will have more rubber contacting the puddle than a narrower, smaller-diameter tire.
What's the tire diameter have to do with it? Well, just ahead of the contact patch, the rubber approaches the road at an angle. On smaller diameter tires, that angle is larger (with respect to the road), and therefore exposes less rubber to the water. The larger diameter tire's "approach angle" is a smaller angle and exposes more rubber to the water.
-Dave
IANAP (I am not a physicist)